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- WLAN (6)
- 802.11b (4)
- PID (3)
- QoS (3)
- Tuning rules (3)
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- Video streaming (3)
- Control (2)
- Control engineering (2)
- IEEE 802.11 (2)
- PID control (2)
- Power Quality (2)
- Resource usage (2)
- UPQC (2)
- VoIp performance (2)
- WLANs (2)
- 802.11 (1)
- Active filters fault diagnosis power capacitors power filters power generation faults power grids power supply quality reactive power wind power plants (1)
- Active power filter (1)
- Adaptive Control Braking (1)
- Antenna (1)
- BER (1)
- BG structure annular ring patch antenna bandwidth 14 MHz to 24 MHz circular antenna electromagnetic band gap frequency 56 MHz to 85 MHz gain 3.5 dB ground plane slot-ring array (1)
- Buffer delay (1)
- Circular-polarization capability crossed-dipole antenna directional base-station antenna dual-linear polarization capability impedance bandwidth planar reflector (1)
- Circularly polarized patch antennas (1)
- Compact wide band shorted folded antenna (1)
- Compactness (1)
- Completion (1)
- Concept drift (1)
- Controller tuning (1)
Articles 1 - 30 of 34
Full-Text Articles in Engineering
Experimental Investigation On Voip Performance And The Resource Utilization In 802.11b Wlans, Miroslaw Narbutt, Mark Davis
Experimental Investigation On Voip Performance And The Resource Utilization In 802.11b Wlans, Miroslaw Narbutt, Mark Davis
Conference papers
In a shared medium network like the 802.11b WLAN, predicting the quality of VoIP calls from the resource usage of the wireless medium is highly desirable. Analyzing the bandwidth usage at the L2/MAC layer may be especially useful for potential QoS provisioning and call admission schemes. This paper experimentally investigates the relationship between resource utilization in WLANS and the quality of VoIP calls transmitted over wireless medium. Specifically we evaluate how the amount of free bandwidth influences transmission impairments (i.e. delay, loss and jitter) and thus call quality. Resource utilization (under the MAC bandwidth components framework) is calculated by a …
Experimental Investigation Of The Effects Of Background Traffic Loads On Streamed Video Over 802.11b Wlans, Tanmoy Debnath, Nicola Cranley, Mark Davis
Experimental Investigation Of The Effects Of Background Traffic Loads On Streamed Video Over 802.11b Wlans, Tanmoy Debnath, Nicola Cranley, Mark Davis
Conference papers
Video is a frame based media and video streaming is often described as “bursty” which has a large impact on the Quality of Service of the video streaming application over WLAN networks. In this paper the impact of background load on the performance of streaming MPEG-4 video with a video server located on the wired network streaming to wireless client is analysed. We experimentally investigate the performance for both uplink and downlink loads. The performance is measured in terms of the key parameters of bit rate, loss rate and mean delay since these are the primary factors that affect the …
Experimental Analysis Of An 802.11b Wireless Mesh Network, Brian Keegan, Karol Kowalik, Mark Davis
Experimental Analysis Of An 802.11b Wireless Mesh Network, Brian Keegan, Karol Kowalik, Mark Davis
Conference papers
Wireless Mesh Networks (WMNs) are a type of radio-based network which require minimal configuration and infrastructure. They can be built using relatively low cost radio and computing platforms. In this paper we attempt to analyze the performance of a simple WNM using various packet sizes as well as a multi-hop WMN.
Performance Of A Variable Speed Double-Fed Induction Generator Wind Turbine During Network Voltage Unbalance Conditions, Joseph Kearney, Michael Conlon
Performance Of A Variable Speed Double-Fed Induction Generator Wind Turbine During Network Voltage Unbalance Conditions, Joseph Kearney, Michael Conlon
Conference papers
The issues of the negative performance of DFIG’s due to supply network voltage unbalance are outlined in this paper. The paper shows the effects that voltage unbalance can have on a DFIG, using the power simulation program DigSilent. The results from simulations show that voltage unbalance affects the both the induction generator and the rotor converter, due to the high unbalanced currents generated. The ability to modify the control strategy of a DFIG to compensate for voltage unbalance is outlined and a proposal to build a test-rig suitable to implement such a system is suggested.
The Effects Of Background Traffic On The End-To-End Delay For Video Streaming Applications Over Ieee 802.11b Wlan Networks, Nicola Cranley, Mark Davis
The Effects Of Background Traffic On The End-To-End Delay For Video Streaming Applications Over Ieee 802.11b Wlan Networks, Nicola Cranley, Mark Davis
Conference papers
The bursty nature of video streaming applications is due to the frame-based structure of video and this has an important impact on the resource requirements of the WLAN, affecting its ability to provide Quality of Service (QoS) particularly under heavily loaded conditions. In this paper we analyse this bursty behaviour in depth. We show how each video frame is queued at the AP causing the packet delay to vary in a sawtooth manner that is related to the frame rate, the number of packets per video frame, and the packet size. We infer the maximum background traffic load that can …
Moving A Part-Time Engineering Course To A Student-Centred Paradigm, Kevin Kelly
Moving A Part-Time Engineering Course To A Student-Centred Paradigm, Kevin Kelly
Conference papers
This paper is a further reflection on two conference papers presented at the World Conference for Continuing Engineering Education (WCCEE) in Vienna in April 2006 and National University of Ireland (NUI) Galway Conference: The Challenge of Diversity: Teaching, Support and Student Learning , June 2006. Both conference papers dealt with different aspects of my experiences of the theoretical and pedagogical changes required in re-design and delivery of a part-time engineering programme for the continuing education development of electrical engineers in the workforce.
An Experimental Analysis Of The Call Capacity Of Ieee 802.11b Wireless Local Area Networks For Voip Telephony, Brian Keegan, Mark Davis
An Experimental Analysis Of The Call Capacity Of Ieee 802.11b Wireless Local Area Networks For Voip Telephony, Brian Keegan, Mark Davis
Conference papers
In this paper we present the results from an experimental study of the call capacity of an IEEE 802.11b network when using VoIP telephony. Experiments include increasing the number of VoIP users in a wireless test-bed and increasing the level of background traffic until network saturation occurs. The experiments allow us to perform an analysis of the access point (AP) buffer dynamics. Results show that the network is capable of supporting up to 16 VoIP stations (STAs). Due to the operation of the IEEE 802.11 medium access control (MAC) mechanism, the AP acts as a bottleneck for all traffic destined …
Gauging Voip Call Quality From 802.11 Wlan Resource Usage, Miroslaw Narbutt, Mark Davis
Gauging Voip Call Quality From 802.11 Wlan Resource Usage, Miroslaw Narbutt, Mark Davis
Conference papers
In this paper we experimentally study the relationship between resource utilization in the wireless LAN and the quality of VoIP calls transmitted over the wireless medium. Specifically we evaluate how its overall capacity is shared between three basic MAC bandwidth components (load, access and free) as the number of VoIP calls increases and how it influences transmission impairments (delay, loss and jitter) and thus call quality. Resource utilization (under the MAC bandwidth components framework) is calculated by a WLAN probe application that passively “sniffs” packets at the L2/MAC layer of the wireless medium and analyses their headers and temporal characteristics. …
The Impact Of Tcp Sliding Window On The Performance Of Ieee 802.11 Wlans, Enrique Roques Gomez, Mark Davis
The Impact Of Tcp Sliding Window On The Performance Of Ieee 802.11 Wlans, Enrique Roques Gomez, Mark Davis
Conference papers
In this paper the TCP sliding window mechanism is experimentally investigated as one of the possible causes of the unfairness often observed as IEEE802.11 wireless LANs. We show how by appropriately sizing the sliding window it is possible to re-introduce fairness into the operation of the WLAN.
Effect Of Free Bandwidth On Voip Performance In 802.11b Wlan Networks, Miroslaw Narbutt, Mark Davis
Effect Of Free Bandwidth On Voip Performance In 802.11b Wlan Networks, Miroslaw Narbutt, Mark Davis
Conference papers
In this paper we experimentally study the relationship between bandwidth utilization in the wireless LAN and the quality of VoIP calls transmitted over the wireless medium. Specifically we evaluate how the amount of free bandwidth decreases as the number of calls increases and how this influences transmission impairments (i.e. delay, loss and jitter) and thus degrades call quality. We show that the amount of free bandwidth is a good indicator for predicting VoIP call quality.
Study Of The Behaviour Of Video Streaming Over Ieee 802.11b Wlan Networks, Nicola Cranley, Mark Davis
Study Of The Behaviour Of Video Streaming Over Ieee 802.11b Wlan Networks, Nicola Cranley, Mark Davis
Conference papers
The performance of video streaming over WLAN networks is not only influenced by the state of the network but also by the encoding configuration parameters of the video stream, such as the video content being streamed, how the vide is encoded and how it is transmitted. In this paper, we analyse the unique delay characteristic of video streaming applications in a WLAN environment. We show that the “burstiness” of video is due to the frame-based nature of encoded video. We show how each video frame is transmitted as a burst of packets that is queued at the Access Point causing …
Experimental Comparison Of Wired Versus Wireless Video Streaming Over Ieee 802.11b Wlans, Tanmoy Debnath, Nicola Cranley, Mark Davis
Experimental Comparison Of Wired Versus Wireless Video Streaming Over Ieee 802.11b Wlans, Tanmoy Debnath, Nicola Cranley, Mark Davis
Conference papers
In this paper the performance of streaming MPEG-4 video with a video server located on the wired network streaming to wireless clients is compared with the performance of a video server located in the wireless network streaming to wireless video clients. We experimentally investigate the performance for a number of concurrent video streams with varying video frame sizes, frame rates and packetisation schemes. The performance is measured in terms of the key parameters of bit rate, loss rate and mean delay. We show how that there is a trade-off for these parameters for a wired and wireless located server. We …
Latency Compensation Control Of Computer Based Control Systems, Aidan O'Dwyer
Latency Compensation Control Of Computer Based Control Systems, Aidan O'Dwyer
Conference papers
This paper discusses the use of a modified Smith predictor for latency (i.e. time delay) compensation, to assist in the implementation of network computer based control systems. Such systems typically have a variable time delay associated with the transfer of information; the modified Smith predictor is robust to time delay variations.
Wideband Directional Base-Station Antenna With Dual-Linear And Circular-Polarization Capabilities, Francisco Lerma, Matthias John, Giuseppe Ruvio, Max Ammann, N. Herscovici
Wideband Directional Base-Station Antenna With Dual-Linear And Circular-Polarization Capabilities, Francisco Lerma, Matthias John, Giuseppe Ruvio, Max Ammann, N. Herscovici
Conference papers
A crossed-dipole antenna providing polarization diversity is presented. The antenna which employs a planar reflector yields high directivity and good isolation between ports over a wide impedance bandwidth, suitable for polarization-agile wireless base-station use. The dipole wing shape is optimised, which yields the wide bandwidth. Matching is achieved using a quarter-wave balanced-to-unbalanced section which also improves the port-to-port isolation. Radiation characteristics for linear and circular polarizations are presented
Performance Improvement Using Simple Pid Controller Tuning Formulae, Aidan O'Dwyer
Performance Improvement Using Simple Pid Controller Tuning Formulae, Aidan O'Dwyer
Conference papers
The proportional integral derivative (PID) controller is the most dominant form of automatic controller in industrial use today. With this technique, it is necessary to adjust the controller parameters according to the nature of the process. Thus, for effective control of a HVDC system, for example, specific values need to be chosen for the P, I and D parameters, which will be different for the values required to control, for example, an induction motor drive. This tailoring of controller to process is known as controller tuning. Controller tuning is easily and effectively performed using tuning rules (i.e. formulae for controller …
Reducing Energy Costs By Optimizing Controller Tuning, Aidan O'Dwyer
Reducing Energy Costs By Optimizing Controller Tuning, Aidan O'Dwyer
Conference papers
The proportional integral derivative (PID) controller is the most dominant form of automatic controller in industrial use today. With this technique, it is necessary to adjust the controller parameters according to the nature of the process. This tailoring of controller to process is known as controller tuning. Controller tuning is easily and effectively performed using tuning rules (i.e. formulae for controller tuning, based on process information). Such tuning rules allow the easy set up of controllers to achieve optimum performance at commissioning. Importantly, they allow ease of re-commissioning if the characteristics of the process change. The paper outlines the results …
Protection Of Dvr Against Short Circuit Faults At The Load Side, Iurie Axente, Malabika Basu, Michael Conlon, Kevin Gaughan
Protection Of Dvr Against Short Circuit Faults At The Load Side, Iurie Axente, Malabika Basu, Michael Conlon, Kevin Gaughan
Conference papers
An additional control scheme has been proposed in this paper for a dynamic voltage restorer (DVR), to protect it against load short circuit conditions. When overcurrents occur in the distribution system, under the proposed scheme the DVR reverses its injected voltage polarity so as to minimise the current flow. The detection method is based on impedance measurement feedback. The advantage of the scheme is that no additional over current device or protection is required for the DVR and it is easy to implement. The proposed control scheme has been validated through simulation.
A Case Study In Modeling And Process Control: The Control Of A Pilot Scale Heating And Ventilation System, Robin Mooney, Aidan O'Dwyer
A Case Study In Modeling And Process Control: The Control Of A Pilot Scale Heating And Ventilation System, Robin Mooney, Aidan O'Dwyer
Conference papers
This paper details the control of a pilot scale laboratory heating and ventilation system. The system is represented in 2x2 multi-input, multi-output (MIMO) form. A process reaction curve identification technique was used to model (in first order lag plus delay - FOLPD - form) the flow process and temperature process portions of the system, over a range of operating conditions. Tests revealed that both processes were continuously non-linear. A gain scheduler with static decoupling was designed, using look-up tables, to continuously interpolate for the most suitable proportional-integral (PI) or proportional-integral-derivative (PID) controller settings and decoupler gains. The contribution of this …
Pi And Pid Controller Tuning Rules: An Overview And Personal Perspective, Aidan O'Dwyer
Pi And Pid Controller Tuning Rules: An Overview And Personal Perspective, Aidan O'Dwyer
Conference papers
The ability of PI and PID controllers to compensate many practical processes has led to their wide acceptance in industrial applications. The requirement to choose two or three controller parameters is most easily done using tuning rules. Starting with a general discussion of industrial practice, the paper provides a survey of additional tuning rules for continuous-time PI and PID control of time-delayed single-input, single-output (SISO) processes, to those explored in a recent book by the author.
Experiences Of Learning And Teaching On A Taught Masters Course In Engineering: From A Didactic Approach To A More Student Centered Learning Approach, Aidan O'Dwyer
Conference papers
This paper reports on, reflects on, and evaluates the author’s experiences of teaching the Advanced Control module on the Masters degree in Advanced Engineering at Dublin Institute of Technology (DIT) over the past four academic years. The teaching approach has evolved from a traditional didactic lecture and laboratory course, with associated assessments, in the first academic year, to the implementation of a more learner-centred approach over the past two academic years. This new approach has been made possible by the appropriate use of real case studies, information technology tools, and web-based virtual laboratories. Assessment methodology has also evolved. In the …
Enhancing Waste Management Through Automatic Control, Aidan O'Dwyer
Enhancing Waste Management Through Automatic Control, Aidan O'Dwyer
Conference papers
Meeting environmental requirements is recognised as one of the six 21st century business drivers for automatic control. The proportional integral (PI) and proportional integral derivative (PID) controllers are the most dominant form of automatic controllers in industrial use today. With these techniques, it is necessary to adjust the controller parameters according to the nature of the process. Thus, for effective control of a heating, cooling and air-conditioning (HVAC) application, for example, specific values need to be chosen for the P, I and D parameters, which will be different for the values required to control, for example, a distillation column. This …
Controlled Braking Scheme For A Wheeled Walking Aid, Eugene Coyle, Aidan O'Dwyer, Eileen Young, Kevin Sullivan, A. Toner
Controlled Braking Scheme For A Wheeled Walking Aid, Eugene Coyle, Aidan O'Dwyer, Eileen Young, Kevin Sullivan, A. Toner
Conference papers
A wheeled walking aid with an embedded controlled braking system is described. The frame of the prototype is based on combining features of standard available wheeled walking aids. A braking scheme has been designed using hydraulic disc brakes to facilitate accurate and sensitive controlled stopping of the walker by the user, and if called upon, by automatic action. Braking force is modulated via a linear actuating stepping motor. A microcontroller is used for control of both stepper movement and for supervisory control. An encoder is used to supervise walker movement in terms of time, distance and speed.
An Approach To Teaching Pid Controller Tuning, Aidan O'Dwyer
An Approach To Teaching Pid Controller Tuning, Aidan O'Dwyer
Conference papers
This paper discusses an approach to the teaching of PID controller tuning methods to students in control engineering at Dublin Institute of Technology. The method involves analytically calculating the gain margin, phase margin and maximum sensitivity for PI and PID controlled systems whose process is modelled in first order lag plus time delay (FOLPD) form. Students can examine the performance of many tuning rules from graphical results, allowing insight to be developed as to the most rational choice of the tuning rule for the application. Some preliminary work done to develop an expert system to allow a greater automation of …
Ber Variation In An Uwb Ofdm Mimo Communications System Based On Measurements Made In A Picocell Wireless Environment, Pat Chambers, Conor Downing, Hussein Baher
Ber Variation In An Uwb Ofdm Mimo Communications System Based On Measurements Made In A Picocell Wireless Environment, Pat Chambers, Conor Downing, Hussein Baher
Conference papers
A picocell UWB MIMO communications system model is considered which has five orthogonal sub-channels, each with its own OFDM signal. The effect of removing the various channel impulse response components which arise due to the multi-path propogation, a phenomenon characteristic of wide band transmission, is considered. This is a measurement based analysis where the measurements, themselves, were made, in a specially constructed enclosure which had reflective surfaces, using specially designed UWB antennas.
A Compact Wide-Band Shorted Folded Antenna, Giuseppe Ruvio, Max Ammann
A Compact Wide-Band Shorted Folded Antenna, Giuseppe Ruvio, Max Ammann
Conference papers
No abstract provided.
Design Of A Wide-Band Printed Antenna Using A Genetic Algorithm On An Array Of Overlapping Sub-Patches, Matthias John, Max Ammann
Design Of A Wide-Band Printed Antenna Using A Genetic Algorithm On An Array Of Overlapping Sub-Patches, Matthias John, Max Ammann
Conference papers
No abstract provided.
Investigation On Annular-Ring Patch Antenna With Ebg Structure, Xiulong Bao, Giuseppe Ruvio, Max Ammann
Investigation On Annular-Ring Patch Antenna With Ebg Structure, Xiulong Bao, Giuseppe Ruvio, Max Ammann
Conference papers
An annular-ring loaded circular patch antenna with slot-ring array of EBG cells on the ground plane is presented. A comparison is made between the annular ring loaded patch on a conventional PEC groundplane and the same patch on a groundplane with a 2x2, a 4x4 and a 6x6 slot-ring EBG array. It was found that the annular-ring patch antenna with a 4 x 4 slot-ring array in the ground plane is superior in the overall performance (gain, impedance and axial-ratio bandwidth). The array of EBG was found to improve gain by 3.5dB and increase the bandwidth of input impedance by …
High Performance Circularly Polarized Antenna Based On Fractal Ebg Structure, Xiulong Bao, Max Ammann, Giuseppe Ruvio, Matthias John
High Performance Circularly Polarized Antenna Based On Fractal Ebg Structure, Xiulong Bao, Max Ammann, Giuseppe Ruvio, Matthias John
Conference papers
Circularly polarized patch antennas have been widely applied in wireless communication system, global positioning system, etc., because of their low-profile, lightweight, ease of fabrication and low lost [1,2]. To achieve high performance for circularly polarized patch antennas, some new structures were reported in the literature, such as antennas array, stack layer antennas, using periodic structures [3-7], etc. In this paper, a high performance circularly polarized low frequency patch antenna based on the compact fractal high-impedance surface EBG structure has been fabricated and experimented. The measured results show that the proposed circularly polarized patch antenna has good performance in impedance bandwidth, …
Synthesising Life-Sciences And Control Engineering: An Outline Survey And A Practical Example, Aidan O'Dwyer
Synthesising Life-Sciences And Control Engineering: An Outline Survey And A Practical Example, Aidan O'Dwyer
Conference papers
There is an increasing interest in life science related areas in the electrical and control engineering community [1]. One manifestation of this interest is the development of interdisciplinary programmes, such as the B.Sc. in Medical Physics and Bioengineering, offered by the Dublin Institute of Technology from September 2005. A significant amount of research work in control engineering has focused on aspects of human physiological system, for example blood glucose regulation [2], cardiovascular modelling and control [3], and limb control [4]. There is an increasing emphasis on interdisciplinary research; in recognition of this, the Institute of Electrical Engineers (IEE) has starting …
Rating Requirements Of A Unified Power Quality Conditioner (Upqc) For Voltage Ride Through Capability Enhancement, N. G. Jayanti, Malabika Basu, Michael Conlon, Kevin Gaughan
Rating Requirements Of A Unified Power Quality Conditioner (Upqc) For Voltage Ride Through Capability Enhancement, N. G. Jayanti, Malabika Basu, Michael Conlon, Kevin Gaughan
Conference papers
The problem of voltage ride through capability of fixed speed wind generation as a result of voltage sags is examined by means of a simulation study. The role of a Unified Power Quality Conditioner (UPQC), which provides both shunt and series compensation, in enhancing the ride through capability is investigated under both full and partial voltage restoration. Results of a study to identify the minimum rating requirements to ensure stability are presented.